One method of joining together two members by the use of weld metal comprises the dropping of molten weld metal against the surfaces to be welded to preheat the same, with the molten metal flowing downwardly past the members to be joined and into a subjacent mold cavity, then dropping additional molten weld metal into a mold cavity closely surrounding the surfaces to be welded and communicating with the subjacent cavity to form the weld. Such method is illustrated and described in U.S. Pat. No. 1,795,332 issued Mar. 10, 1931, in the name of J. H. Deppeler. Characteristic of the method of this Deppeler patent is that the molten is obtained by an exothermic reaction, which creates the metal from its oxide and provides that metal at a high temperature by a rapid evolution of heat during the reaction. An example is the Thermit reaction.